The present invention relates to a main layout rack structure for communication exchange, and more particularly to a layout rack structure including two cooperative PC boards to reduce the volume of the rack and provide connections for more telephones. Also, the rack structure simplifies telephone line connections.
The existing main layout rack structure used in a telephone exchange is composed of several terminal boards 10 sequentially overlaid on each other as shown in FIG. 1. The upper side of the terminal board 10 is formed with ten pairs of incoming line engaging troughs 11. The lower side of the terminal board 10 is formed with ten pairs of opposite outgoing line engaging troughs 12. The incoming line engaging troughs 11 serve to engage with lines connected to the exchange, while the outgoing line engaging troughs 12 serve to engage with the lines connected to the telephones. Each telephone corresponds to a pair of incoming line engaging troughs 11 and a pair of outgoing line engaging troughs 12. Therefore, each terminal board 10 at most provides connections for ten telephones. In the case of more telephones, a certain number of terminal boards 10 must be added.
A main layout rack structure employing semiconductor techniques has been developed to replace the above structure. Such improved layout rack has smaller volume. However, the expense for such semiconductor techniques is over twenty times the cost for the conventional layout rack. Therefore, rack structures employing semiconductor techniques are not widely used.
The above conventional layout rack structure has the following shortcomings:
1. Each terminal board 10 is applicable to ten lines (that is, ten telephones). Therefore, in the case of one hundred telephones, ten terminal boards will be necessary for providing connections for the one hundred telephones. As a result, the volume will increase ten times and much room will be occupied. PA1 2. When connecting each telephone, one set of two lines must be connected to one set of incoming line engaging troughs 11 of the terminal board 10 from the exchange and then one set of two lines must be engaged with the corresponding outgoing line engaging troughs 12 and connected to the telephone. Such procedure is troublesome and inconvenient and the more telephones there are, the more complicated the lines are.